plib-devel

Re: [Plib-devel] PLIB 'Neat stuff' library

[Joel U. <joe...@ya...>]

> Dave McClurg wrote:
> 
> > "Vallevand, Mark K" wrote:
> > >
> > > Steve, are you planning on collecting some neat stuff into PLIB?
> An
> > > auxiliary library of stuff.  I have a few small, useful classes
> that
> > > someone else might find handy.  The auxiliary library would
> > be a good
> > > places to put collections of textures, wav files, mod files
> > and models.
> >
> > When you get back, Steve, I wonder about something like this for the
> 
> > more complex primtives for PPE - sphere/cylinder that sort of thing.
> I
> > think that they might be better in an auxillary library to ssg,
> which
> > builds onto the features of ssg.
> >
> > Just a suggestion to save all this continual adding to ssg simply
> for
> > PPE.
> >
> > Bye - Joel.
> 
> Is the KeyFlier something that could be moved out of ssg into the
> auxillary library?
> 
> --Dave

Makes sense to me, but Steve might disagree.

Bye - Joel.

[Plib-devel] ssgLoadASE now uses ssgVtxArray

[Dave M. <Dav...@dy...>]

I fixed ssgLoadASE so it uses ssgVtxArray.
This significantly lowers the # of verticies and should speed things up for
large models

--Dave

RE: [Plib-devel] PLIB 'Neat stuff' library

[Dave M. <Dav...@dy...>]

> "Vallevand, Mark K" wrote:
> > 
> > Steve, are you planning on collecting some neat stuff into PLIB?  An
> > auxiliary library of stuff.  I have a few small, useful classes that
> > someone else might find handy.  The auxiliary library would 
> be a good
> > places to put collections of textures, wav files, mod files 
> and models.
> 
> When you get back, Steve, I wonder about something like this for the
> more complex primtives for PPE - sphere/cylinder that sort of thing. I
> think that they might be better in an auxillary library to ssg, which
> builds onto the features of ssg.
> 
> Just a suggestion to save all this continual adding to ssg simply for
> PPE.
> 
> Bye - Joel.

Is the KeyFlier something that could be moved out of ssg into the
auxillary library?

--Dave

Re: [Plib-devel] PLIB 'Neat stuff' library

[Joel U. <joe...@ya...>]

"Vallevand, Mark K" wrote:
> 
> Steve, are you planning on collecting some neat stuff into PLIB?  An
> auxiliary library of stuff.  I have a few small, useful classes that
> someone else might find handy.  The auxiliary library would be a good
> places to put collections of textures, wav files, mod files and models.

When you get back, Steve, I wonder about something like this for the
more complex primtives for PPE - sphere/cylinder that sort of thing. I
think that they might be better in an auxillary library to ssg, which
builds onto the features of ssg.

Just a suggestion to save all this continual adding to ssg simply for
PPE.

Bye - Joel.

RE: [Plib-devel] anyone have plib for windows?

[Dave M. <Dav...@dy...>]

According to the PLIB readme.win32:

	Borland C++:
	~~~~~~~~~~~~
	"Heil, David G. SDX" <Da...@HP...> contributed a set of
	Borland bpg/bpr files. I know nothing more about what may be
	required in order to use them.

If that doesn't help, you should look at Makefile.am in each of the
src folders.  They list the files in each library.
Using that information, it should be pretty straigh-forward
to compile them on any system.
To get started quickly, just throw all the files in one folder
and link them together without libraries.

Good luck,
--Dave

> Does anyone have plib pre-compiled for windowz? Or maybe some 
> makefiles for
> the free Borland compiler. I want to try and port my GL apps 
> to windowz you
> see, but without plib under windows I'm kinda stuck. 
> 
> Thanks in advance,
> 
> Arthur.

R: [Plib-devel] anyone have plib for windows?

[Paolo L. <p.l...@ci...>]

I can just put at your disposal the plib 1.2 *Cygnus* .a libs (B20.1, thus
compiled with g++/gcc 2.95.2) - so if you like you can pick these at
ftp://ftp.cira.it/paolo/plib/lib/cygnus/. These just require Cygwin1,
Glut32, GLU32, OpenGL32 dlls. Anyway you can freely contact me if you plan
to switch to Cygnus on Windows.


----------------------------------------------------------------------------
-
Paolo Leoncini						phone:  +39 (0823) 623134
Scientific Visualization Group			fax:    +39 (0823) 623126
CIRA - Italian Center for Aerospace Researches	p.l...@ci...
Via Maiorise - 81043 Capua (CE) Italy		www.cira.it/research/vis

> -----Messaggio originale-----
> Da: pli...@li...
> [mailto:pli...@li...]Per conto di Arthur
> Yarwood
> Inviato: lunedì 24 luglio 2000 12.22
> A: pli...@li...
> Oggetto: [Plib-devel] anyone have plib for windows?
>
>
> Does anyone have plib pre-compiled for windowz? Or maybe some
> makefiles for
> the free Borland compiler. I want to try and port my GL apps to
> windowz you
> see, but without plib under windows I'm kinda stuck.
>
> Thanks in advance,
>
> Arthur.
>
>
> _______________________________________________
> plib-devel mailing list
> pli...@li...
> http://lists.sourceforge.net/mailman/listinfo/plib-devel
>

Re: [Plib-devel] Bug with sign of pitch?

[Wolfram K. <w_...@rz...>]

Dave wrote:

>   M(3,0) = -eyex; M(3,1) = -eyey; M(3,2) = -eyez; M(3,3) = 1.0;

I think this is wrong. This is done differently in Mesa, Mesa uses an
extra glTranslate. People wanting to use this code with plib should
check this.

Bye bye,
Wolfram Kuss.

[Plib-devel] PLIB 'Neat stuff' library

[Vallevand, M. K <Mar...@UN...>]

Steve, are you planning on collecting some neat stuff into PLIB?  An
auxiliary library of stuff.  I have a few small, useful classes that
someone else might find handy.  The auxiliary library would be a good
places to put collections of textures, wav files, mod files and models.

Regards.
Mark K Vallevand   ma...@rs...
Never try and teach a pig to sing: it's a waste of time, and it annoys
the pig.

[Plib-devel] anyone have plib for windows?

[Arthur Y. <u97...@bo...>]

Does anyone have plib pre-compiled for windowz? Or maybe some makefiles for
the free Borland compiler. I want to try and port my GL apps to windowz you
see, but without plib under windows I'm kinda stuck. 

Thanks in advance,

Arthur.

Re: [Plib-devel] MSVC

[Wolfram K. <w_...@rz...>]

I just compiled all the projects from the workspace that is supplied
with plib. I had no problems with pui or sl. The sl-project does NOT
contain slHack.cxx. However, no os-project is included.

Bye bye,
Wolfram Kuss.

[Plib-devel] MSVC

[<Va...@t-...>]

Hi,

I wanted to compile PLIB with MSVC (using my own workspace) and got some
problems.

- in os/DynLib.cpp MSVC couldn't find a "Pch.h" or a "Os.h". So I
  uncommented them.
- after changing "__WIN32__" to "_WIN32" I could finally compile
  DynLib.cpp

- pu.h made some problems as I had to define GLUT_IS_PRESENT. Couldn't
  we make it the default by changing the top of pu.h from:

#ifndef PU_NOT_USING_GLUT
#  ifdef FREEGLUT_IS_PRESENT
#    include <GL/freeglut.h>
#  else
#    ifdef GLUT_IS_PRESENT
#      include <GL/glut.h>
#    else
       /* No GLUT?!? */
#    endif
#  endif
#endif

to:

#ifndef PU_NOT_USING_GLUT
#  ifdef FREEGLUT_IS_PRESENT
#    include <GL/freeglut.h>
#  else
#    include <GL/glut.h>
#  endif
#endif

- sl/slhack.cxx has a few functions that don't return a value 
  although they have to. This happens in the lines 690, 704, 
  765 and 789. This also breakes MSVC.

CU,
Christian

Re: [Plib-devel] Joystick problem

[Steve B. <sjb...@ai...>]

Steve Baker wrote:
 
> Risto S Varanka wrote:

> > Btw, do people often have problems with the joystick support?

Almost never.

99% of PLIB problems are of the "My OpenGL isn't installed right"
kind.

> > Maybe the example could have more diagnostic features,

Yes - it should.  The example programs are kinda sad, unloved
packages - it's very unglamorous to work on them - but it needs
to be done.

>   chgrm root /dev/js{0,1}
    ^^^^^
   Ooops!  That should have been 'chgrp'!


-- 
Steve Baker   HomeEmail: <sjb...@ai...>
              WorkEmail: <sj...@li...>
              HomePage : http://web2.airmail.net/sjbaker1
              Projects : http://plib.sourceforge.net
                         http://tuxaqfh.sourceforge.net
                         http://tuxkart.sourceforge.net
                         http://prettypoly.sourceforge.net

Re: [Plib-devel] Joystick problem

[Steve B. <sjb...@ai...>]

Risto S Varanka wrote:
> 
> Thanks for help, Stephen! My joystick works just nice in the JS example
> as well now, and I'm one happy hacker. (If only I got my OpenGL
> working too ;)
> 
> I'm sorry to disappoint you, but it was a simple permission
> problem.  I had overlooked the obvious :) Btw, do people often
> have problems with the joystick support? Maybe the example could
> have more diagnostic features, like in my case it could have said:
> "No permissions to use joystick /dev/js0.  The permissions on file
> /dev/js0 are "rw-rw----" - is this correct?"

No.

rw-rw---- only grants permission to the 'owner' of /dev/js0 - who
is presumably 'root' - and to members of the 'group' that /dev/js0
belongs to - which is presumably also 'root'.  Other users who
are not 'root' or members of the 'root' group will be denied
permission to read or write it.

You need crw-rw-rw-.  Log in as 'root' (or run 'su') and type:

  chown root /dev/js{0,1}
  chgrm root /dev/js{0,1}
  chmod a+rw /dev/js{0,1}

...just to be sure.  On my machine:

  > ls -l /dev/js*
  crw-rw-rw-   1 root     root      15,   0 Mar 11 04:11 /dev/js0
  crw-rw-rw-   1 root     root      15,   1 Mar 11 04:11 /dev/js1

-- 
Steve Baker   HomeEmail: <sjb...@ai...>
              WorkEmail: <sj...@li...>
              HomePage : http://web2.airmail.net/sjbaker1
              Projects : http://plib.sourceforge.net
                         http://tuxaqfh.sourceforge.net
                         http://tuxkart.sourceforge.net
                         http://prettypoly.sourceforge.net

[Plib-devel] SigGraph.

[Stephen J B. <sj...@li...>]

Several people have asked about SigGraph...I guess quite a few
of us developer types will be there and it would be cool if we
could meet up somewhere.

The most obvious place would be the informal Birds Of a Feather
(BOF) meetings for Linux/OpenGL/Mesa:
 
|   * OpenGL Birds of a Feather - 7/26
|     6:30PM - 8 PM Hilton Hotel, Napoleon
|     Room, 3rd Floor.
|
|   * Linux 3D Birds of a Feather 7/27
|     6:30PM - 8 PM Hilton Riverside,
|     Versaille Ballroom.                                                                    

I plan to attend both of those - it would be nice to get some
face-to-face contact and instanciate some of those 'virtual beers'
that I've been promised!  :-)

Steve Baker                      (817)619-2657 (Vox/Vox-Mail)
L3Com/Link Simulation & Training (817)619-2466 (Fax)
Work: sj...@li...           http://www.link.com
Home: sjb...@ai...       http://web2.airmail.net/sjbaker1

[Plib-devel] Joystick problem

[Risto S V. <rva...@cc...>]

Thanks for help, Stephen! My joystick works just nice in the JS example
as well now, and I'm one happy hacker. (If only I got my OpenGL
working too ;) 

I'm sorry to disappoint you, but it was a simple permission
problem.  I had overlooked the obvious :) Btw, do people often
have problems with the joystick support? Maybe the example could
have more diagnostic features, like in my case it could have said:
"No permissions to use joystick /dev/js0.  The permissions on file
/dev/js0 are "rw-rw----" - is this correct?"

-- 
Risto Varanka | http://www.helsinki.fi/~rvaranka/		
ris...@he...

[Plib-devel] Joystick problems (cont.)

[Risto S V. <rva...@cc...>]

I noticed I sent my message to the wrong list accidentally (this
would really belong to plib-users I gather), sorry about that.
Anyways, here's some additional info. 

Originally I used the version 1.0.20 of Plib, then I upgraded to
1.2.0, but the problem still persists:

fun13:/usr/src/plib-1.2.0/examples/plib_examples-1.1.8/examples/js$ ./js_demo 
Joystick test program.
~~~~~~~~~~~~~~~~~~~~~
Joystick 0 not detected
Joystick 1 not detected

I am using Debian Potato with version 2.2.15 of the kernel, and
joystick driver v1.2.15. 

-- 
Risto Varanka
ris...@he...
http://www.helsinki.fi/~rvaranka/Linux.html		

Re: [Plib-devel] Joystick problem

[Stephen J B. <sj...@li...>]

Risto S Varanka wrote:
 
> My joystick (CH Combatstick) works fine in Linux itself, but not
> with Plib's JS. The joy-analog module loads fine with the correct
> parameters, and it works perfectly in jstest. However, the JS
> example program says that no joysticks are found. (notWorking
> returns true.)
> 
> What could be the problem? How can I investigate it? I haven't yet
> tried other programs or hacking the Plib code.  (I didn't get
> joystick working with one of my own Plib experiments, though.)

That's certainly an unusual problem.  I havn't heard of anyone
with that kind of a problem before.

Hence, I'm rather at a loss to know what to suggest - so here
are a bunch of questions that might show up something useful:

* When you ran './configure' on PLIB, did it say that it had
  detected 'linux/joystick.h' or did it say that 'joystick.h'
  had been found?

  It *should* be linux/joystick.h for Linux systems - if it
  isn't then there is something wrong with your installation
  of the joystick drivers.

* That being the case, could you look in /usr/include/linux/joystick.h
  and tell me what 'JS_VERSION' is defined as.

     grep JS_VERSION /usr/include/linux/joystick.h

  ...should do the trick.

* Also, could you tell me which version of PLIB you have and what
  Linux distribution and Kernel version you are running.

* Is it possible that the joystick header file and your joystick
  driver are out of sync?  Have you ever upgraded either of them?

* Does the file /dev/js0 exist?  Does it have '-rw-rw-rw'
  permissions?

If you *really* want to investigate this some more by digging
around in the code, I would add:

    if ( fd < 0 ) { perror("JS-open") ; exit(1) ; }

...just after:

    fd = ::open ( fname, O_RDONLY | O_NONBLOCK ) ;

...on about line 176 of src/js/js.h in PLIB.

That will let us see whether the joystick device is being
opened correctly (I suspect it is not - but I don't know
why not).

If it *is* being opened correctly then...I'm *really*
puzzled...there are three possibilities:

   If you have the old joystick driver (unlikely) then
   I can't imagine what could be wrong.

   If the system *thinks* you have the old driver - but
   you actually have the new driver - or vice-versa then
   who knows what crap could be happening. (Hence my
   questions about headers and upgrades).

   If you have the new joystick driver (I think you must
   have since the old one wasn't called 'joy-analog' IIRC)
   then perhaps the 'ioctl' on lines 219 and 220 are somehow
   not returning.  Hmmm - I should be checking for error there
   and I'm not...*BAD* programmer :-)

   Add:

   if ( errno != 0 ) perror("JS-ioctl");

   ...after each ioctl and the fcntl, then print out:

   fprintf(stderr, "Axes=%d Buttons=%d\n", num_axes, num_buttons ) ;

   ...and let's see exactly what it detected.

Good luck - and *please* let me know what you find.

Steve Baker                      (817)619-2657 (Vox/Vox-Mail)
L3Com/Link Simulation & Training (817)619-2466 (Fax)
Work: sj...@li...           http://www.link.com
Home: sjb...@ai...       http://web2.airmail.net/sjbaker1

[Plib-devel] Joystick problem

[Risto S V. <rva...@cc...>]

Hi

My joystick (CH Combatstick) works fine in Linux itself, but not
with Plib's JS. The joy-analog module loads fine with the correct
parameters, and it works perfectly in jstest. However, the JS
example program says that no joysticks are found. (notWorking
returns true.)

What could be the problem? How can I investigate it? I haven't yet
tried other programs or hacking the Plib code.  (I didn't get
joystick working with one of my own Plib experiments, though.)

-- 
Risto Varanka | http://www.helsinki.fi/~rvaranka/		
ris...@he...

RE: [Plib-devel] ssg animation

[Dave M. <Dav...@dy...>]

Steve wrote :
> > i was thinking that ssgSelector would replace the bitset with
> > an array of bools.  select() would be rewritten as:
> > 
> >   void select ( unsigned int s )
> >   {
> >     for ( int i=0; i<max_kids && i<32; i++ )
> >       selection [i] = ( (1<<i) & s ) != 0 ;
> >   }
> > 
> > does that work for you?
> 
> Do you want me to do this BTW?   If you are not
> already 'on the case', I could get it done in an
> hour or so - maybe tonight.
> 
it's all yours.
i'll pound on the Blender VRML loader tonite.

--Dave

Re: [Plib-devel] ssg animation

[Steve B. <sjb...@ai...>]

> Dave McClurg wrote:
> 
> Steve wrote:
> > > ssgSelector would allow more than 32 frames by adding a
> > > max_kids param to the constructor
> >
> > What about the current ability (which I use quite a bit) to
> > pass an integer mask with one bit per child object to
> > enable you to select multiple child objects at once?
> >
> i was thinking that ssgSelector would replace the bitset with
> an array of bools.  select() would be rewritten as:
> 
>   void select ( unsigned int s )
>   {
>     for ( int i=0; i<max_kids && i<32; i++ )
>       selection [i] = ( (1<<i) & s ) != 0 ;
>   }
> 
> does that work for you?

Do you want me to do this BTW?   If you are not
already 'on the case', I could get it done in an
hour or so - maybe tonight.

-- 
Steve Baker   HomeEmail: <sjb...@ai...>
              WorkEmail: <sj...@li...>
              HomePage : http://web2.airmail.net/sjbaker1
              Projects : http://plib.sourceforge.net
                         http://tuxaqfh.sourceforge.net
                         http://tuxkart.sourceforge.net
                         http://prettypoly.sourceforge.net

Re: [Plib-devel] ssg animation

[Steve B. <sjb...@ai...>]

> Dave McClurg wrote:
> 
> Steve wrote:
> > > ssgSelector would allow more than 32 frames by adding a
> > > max_kids param to the constructor
> >
> > What about the current ability (which I use quite a bit) to
> > pass an integer mask with one bit per child object to
> > enable you to select multiple child objects at once?
> >
> i was thinking that ssgSelector would replace the bitset with
> an array of bools.  select() would be rewritten as:
> 
>   void select ( unsigned int s )
>   {
>     for ( int i=0; i<max_kids && i<32; i++ )
>       selection [i] = ( (1<<i) & s ) != 0 ;
>   }
> 
> does that work for you?

We need to preserve the current functionality of 'select(unsigned int)' then -
and add a new 'select(unsigned int *)' to allow you to pass an array of select
bits or something.

Yep - that'll work.


-- 
Steve Baker   HomeEmail: <sjb...@ai...>
              WorkEmail: <sj...@li...>
              HomePage : http://web2.airmail.net/sjbaker1
              Projects : http://plib.sourceforge.net
                         http://tuxaqfh.sourceforge.net
                         http://tuxkart.sourceforge.net
                         http://prettypoly.sourceforge.net

RE: [Plib-devel] ssg animation

[Dave M. <Dav...@dy...>]

Steve wrote:
> > ssgSelector would allow more than 32 frames by adding a 
> > max_kids param to the constructor
>
> What about the current ability (which I use quite a bit) to 
> pass an integer mask with one bit per child object to
> enable you to select multiple child objects at once?
>
i was thinking that ssgSelector would replace the bitset with
an array of bools.  select() would be rewritten as:

  void select ( unsigned int s )
  {
    for ( int i=0; i<max_kids && i<32; i++ )
      selection [i] = ( (1<<i) & s ) != 0 ;
  }

does that work for you?

> Yes - but there are times when frame-locked synchronisation 
> is *CRITICAL*.
> 
> One example is in a weather simulation model we have at work that does
> lightning bolts...

cool example. i'll have to remember that.

> > Please tell me your thoughts
> 
> Wibble, wibble, wibble.
> 
>   -- You did ask.  :-)
> 
lol.

--Dave McClurg

RE: [Plib-devel] Bug with sign of pitch?

[Dave M. <Dav...@dy...>]

rather than translate into an ssg XYZ - HPR coord structure
why not just set the camera matrix?

i hacked this from LookAt in Mesa-3.2/src-glu/glu.c
but i haven't tested it yet

void ssgLookAt( GLdouble eyex, GLdouble eyey, GLdouble eyez,
                GLdouble centerx, GLdouble centery, GLdouble centerz,
                GLdouble upx, GLdouble upy, GLdouble upz )
{
   sgMat4 m;
   GLdouble x[3], y[3], z[3];
   GLdouble mag;

   /* Make rotation matrix */

   /* Z vector */
   z[0] = eyex - centerx;
   z[1] = eyey - centery;
   z[2] = eyez - centerz;
   mag = sqrt( z[0]*z[0] + z[1]*z[1] + z[2]*z[2] );
   if (mag) {  /* mpichler, 19950515 */
      z[0] /= mag;
      z[1] /= mag;
      z[2] /= mag;
   }

   /* Y vector */
   y[0] = upx;
   y[1] = upy;
   y[2] = upz;

   /* X vector = Y cross Z */
   x[0] =  y[1]*z[2] - y[2]*z[1];
   x[1] = -y[0]*z[2] + y[2]*z[0];
   x[2] =  y[0]*z[1] - y[1]*z[0];

   /* Recompute Y = Z cross X */
   y[0] =  z[1]*x[2] - z[2]*x[1];
   y[1] = -z[0]*x[2] + z[2]*x[0];
   y[2] =  z[0]*x[1] - z[1]*x[0];

   /* mpichler, 19950515 */
   /* cross product gives area of parallelogram, which is < 1.0 for
    * non-perpendicular unit-length vectors; so normalize x, y here
    */

   mag = sqrt( x[0]*x[0] + x[1]*x[1] + x[2]*x[2] );
   if (mag) {
      x[0] /= mag;
      x[1] /= mag;
      x[2] /= mag;
   }

   mag = sqrt( y[0]*y[0] + y[1]*y[1] + y[2]*y[2] );
   if (mag) {
      y[0] /= mag;
      y[1] /= mag;
      y[2] /= mag;
   }

#define M(row,col)  m[row][col]
   M(0,0) = x[0];  M(0,1) = x[1];  M(0,2) = x[2];  M(0,3) = 0.0;
   M(1,0) = y[0];  M(1,1) = y[1];  M(1,2) = y[2];  M(1,3) = 0.0;
   M(2,0) = z[0];  M(2,1) = z[1];  M(2,2) = z[2];  M(2,3) = 0.0;
   M(3,0) = -eyex; M(3,1) = -eyey; M(3,2) = -eyez; M(3,3) = 1.0;
#undef M

   ssgSetCamera( m ) ;
}


> Last I looked I didn't see anything like this, but what I would really
> like is some code that would take a directional vector and an up
> vector and translate this into an ssg XYZ - HPR coord structure.
> 
> What I'd like to use this for is given I know my camera position, and
> the position of something I want centered on the screen, I want to
> look directly at it (with control over the up direction.)  For
> example, a chase plane view in a flight sim.
> 
> It's probably a simple thing to impliment, but I just haven't had a
> chance to sit down and think it through ... and if someone has already
> done the work I'd happily use that. :-)
> 
> Regards,
> 
> Curt.

Re: [Plib-devel] Bug with sign of pitch?

[Curtis L. O. <cu...@me...>]

Last I looked I didn't see anything like this, but what I would really
like is some code that would take a directional vector and an up
vector and translate this into an ssg XYZ - HPR coord structure.

What I'd like to use this for is given I know my camera position, and
the position of something I want centered on the screen, I want to
look directly at it (with control over the up direction.)  For
example, a chase plane view in a flight sim.

It's probably a simple thing to impliment, but I just haven't had a
chance to sit down and think it through ... and if someone has already
done the work I'd happily use that. :-)

Regards,

Curt.

Wolfram Kuss writes:
> BTW, I game developers might use this code as well.
> I use it for camera-movement (when I do a "make object fully
> visible").
> Its quite simple, but perhaps you want to put it into plib?
> 
> Here is the function:
> 
> --------------------- cut ------------------------------
> void /*sg*/Vec3fromHPR ( sgVec3 vec3, const sgVec3 hpr ) 
> // If hpr are the hpr of the camera, then this function gives the
> normalised
> // viewing direction. Of course roll is lost in this conversion.
> {
>   double ch, sh, cp, sp; 
> 
>   if ( hpr[0] == SG_ZERO )
>   {
>     ch = SGD_ONE ;
>     sh = SGD_ZERO ;
>   }
>   else
>   {
>     sh = (SGfloat) sin( (double)( hpr[0] * SG_DEGREES_TO_RADIANS )) ;
>     ch = (SGfloat) cos( (double)( hpr[0] * SG_DEGREES_TO_RADIANS )) ;
>   }
> 
>   if ( hpr[1] == SG_ZERO )
>   {
>     cp = SGD_ONE ;
>     sp = SGD_ZERO ;
>   }
>   else
>   {
>     sp = sin( (double)( hpr[1] * SG_DEGREES_TO_RADIANS )) ;
>     cp = cos( (double)( hpr[1] * SG_DEGREES_TO_RADIANS )) ;
>   }
>   vec3[0] = (SGfloat)( -sh * cp ) ;
>   vec3[1] = (SGfloat)( ch * cp ) ;
>   vec3[2] = (SGfloat)(  sp ) ;
> // rest is check
>   sgVec3 hprCheck;
>   sgHPRfromVec3 ( hprCheck, vec3) ;
>   if(0.01<abs(hprCheck[0]-hpr[0]))
>     fprintf(stderr,"\n*** Heading: %f vs %f***\n",hprCheck[0],hpr[0]);
>   if(0.01<abs(hprCheck[1]-hpr[1]))
>     fprintf(stderr,"\n*** Pitch: %f vs %f ***\n",hprCheck[1],hpr[1]);
>   
> 
> }
> --------------------- cut ------------------------------
> 
> Bye bye,
> Wolfram Kuss.
> 
> 
> _______________________________________________
> plib-devel mailing list
> pli...@li...
> http://lists.sourceforge.net/mailman/listinfo/plib-devel

-- 
Curtis Olson   Human Factors Research Lab       Flight Gear Project
Twin Cities    cu...@hf...                cu...@fl...
Minnesota      http://www.menet.umn.edu/~curt   http://www.flightgear.org

[Plib-devel] Bug with sign of pitch?

[Wolfram K. <w_...@rz...>]

I have a trivial question:

If I am in a slightly ascending aeroplane, is my pitch positive?
I would guess so, but looking at

void sgHPRfromVec3 ( sgVec3 hpr, const sgVec3 src )

at the line

  hpr[1] = -(SGfloat) atan2 ( tmp [ 2 ], sqrt ( sgSquare ( tmp [ 0 ] )
+ sgSquare ( tmp [ 1 ] ) ) ) *
SG_RADIANS_TO_DEGREES ;

it seems to be negative, is that correct?

Here is the reason for my question:
While sg contains a function to convert a cartesian Vec3 into a HPR,
the other conversion was missing and I implemented it for PPE by
copying code from sgMakeCoordMat4. It seems to work in PPE,
but when I converted the result back as a check, I get inverted pitch.
Is the bug in my new function or in plib, for example sgHPRfromVec3 ?

BTW, I game developers might use this code as well.
I use it for camera-movement (when I do a "make object fully
visible").
Its quite simple, but perhaps you want to put it into plib?

Here is the function:

--------------------- cut ------------------------------
void /*sg*/Vec3fromHPR ( sgVec3 vec3, const sgVec3 hpr ) 
// If hpr are the hpr of the camera, then this function gives the
normalised
// viewing direction. Of course roll is lost in this conversion.
{
  double ch, sh, cp, sp; 

  if ( hpr[0] == SG_ZERO )
  {
    ch = SGD_ONE ;
    sh = SGD_ZERO ;
  }
  else
  {
    sh = (SGfloat) sin( (double)( hpr[0] * SG_DEGREES_TO_RADIANS )) ;
    ch = (SGfloat) cos( (double)( hpr[0] * SG_DEGREES_TO_RADIANS )) ;
  }

  if ( hpr[1] == SG_ZERO )
  {
    cp = SGD_ONE ;
    sp = SGD_ZERO ;
  }
  else
  {
    sp = sin( (double)( hpr[1] * SG_DEGREES_TO_RADIANS )) ;
    cp = cos( (double)( hpr[1] * SG_DEGREES_TO_RADIANS )) ;
  }
  vec3[0] = (SGfloat)( -sh * cp ) ;
  vec3[1] = (SGfloat)( ch * cp ) ;
  vec3[2] = (SGfloat)(  sp ) ;
// rest is check
  sgVec3 hprCheck;
  sgHPRfromVec3 ( hprCheck, vec3) ;
  if(0.01<abs(hprCheck[0]-hpr[0]))
    fprintf(stderr,"\n*** Heading: %f vs %f***\n",hprCheck[0],hpr[0]);
  if(0.01<abs(hprCheck[1]-hpr[1]))
    fprintf(stderr,"\n*** Pitch: %f vs %f ***\n",hprCheck[1],hpr[1]);
  

}
--------------------- cut ------------------------------

Bye bye,
Wolfram Kuss.